Display substrate and display apparatus including the same

ABSTRACT

A display substrate includes a data line extending in a first direction, a first transistor including a first channel area overlapping the data line and a first control electrode which overlaps the first channel area and has a substantially same shape as that of the first channel area in an overlap area in which the first control electrode overlaps the first channel area, a scan line extending in a second direction crossing the first direction, a first voltage line extending in the first direction and transfers a first driving signal, a first capacitor including an extension electrode which overlaps the first control electrode and extends in the second direction from the first voltage line and a second capacitor including an overlap electrode overlapping the data line.

This application claims priority to Korean Patent Application No.10-2016-0145851, filed on Nov. 3, 2016, and all the benefits accruingtherefrom under 35 U.S.C. §119, the content of which in its entirety isherein incorporated by reference.

BACKGROUND 1. Field

Exemplary embodiments of the invention relate to a display substrate anda display apparatus including the display substrate. More particularly,exemplary embodiments of the invention relate to a display substrate forimproving a display quality and a display apparatus including thedisplay substrate.

2. Description of the Related Art

Recently, various types of flat panel display devices that improve upondisadvantages of a cathode ray tube (“CRT”), such as a heavy weight anda large volume, have been developed. The flat panel display devicesinclude a liquid crystal display (“LCD”) device, a field emissiondisplay (“FED”) device, a plasma display panel (“PDP”), an organic lightemitting display device, etc.

The organic light emitting display device has various advantages such asrapid response speed and low power consumption because the organic lightemitting display device among the flat panel display devices displays animage using an organic light emitting diode (“OLED”) that emits a lightbased on recombination of electrons and holes.

SUMMARY

Exemplary embodiments of the invention provide a display substrate forimproving a display quality.

Exemplary embodiments of the invention provide a display apparatusincluding the display substrate.

According to an exemplary embodiment of the invention, there is provideda display substrate. The display substrate includes a data lineextending in a first direction, a first transistor including a firstchannel area overlapping the data line and a first control electrodewhich overlaps the first channel area and has a substantially same shapeas that of the first channel area in an overlap area in which the firstcontrol electrode overlaps the first channel area, a scan line extendingin a second direction crossing the first direction, a first voltage linewhich extends in the first direction and transfers a first drivingsignal, a first capacitor including an extension electrode whichoverlaps the first control electrode and extends in the second directionfrom the first voltage line, and a second capacitor including an overlapelectrode overlapping the data line.

In an exemplary embodiment, the display substrate may further include asecond voltage line which is connected to the first transistor andtransfers the first power source signal, where the data line is disposedbetween the first voltage line and the second voltage line adjacent tothe first voltage line in the second direction.

In an exemplary embodiment, the display substrate may further include asecond transistor including a second control electrode connected to thescan line, a first electrode connected to the first control electrodeand a second electrode connected to the overlap electrode, a thirdvoltage line which is parallel with the scan line and transfers a seconddriving signal, and a third transistor including a third controlelectrode connected to the third voltage line, a first electrodeconnected to the first voltage line and a second electrode connected tothe overlap electrode.

In an exemplary embodiment, the display substrate may further include afirst insulating interlayer disposed between the first control electrodeand the extension electrode, and including a high dielectric constantmaterial.

In an exemplary embodiment, the display substrate may further include asecond insulating interlayer disposed between the extension electrodeand the data line and a third insulating interlayer disposed between thedata line and the overlap electrode.

In an exemplary embodiment, the display substrate may further include anorganic light emitting diode including an anode electrode connected tothe overlap electrode, a cathode electrode which receives a second powersource signal and an organic light emitting layer disposed between theanode electrode and the cathode electrode.

According to an exemplary embodiment of the invention, there is provideda display apparatus. The display apparatus includes a first displaysubstrate including an m-th data line extending in a first direction, afirst transistor including a first channel area overlapping the m-thdata line and a first control electrode which overlaps the first channelarea and has a substantially same shape as that of the first channelarea in an overlap area in which the first control electrode overlapsthe first channel area, an n-th scan line extending in a seconddirection crossing the first direction, a first capacitor including anextension electrode overlapping the first control electrode, a secondcapacitor including an overlap electrode overlapping the m-th data line,and an organic light emitting diode including an anode electrodeconnected to the overlap electrode and an organic light emitting layer,and a second display substrate opposing to the first display substrate.

In an exemplary embodiment, the first display substrate may furtherinclude a first voltage line which extends in the first direction andtransfers a first driving signal, and a second voltage line which isconnected to the first transistor and transfers the first power sourcesignal, where the m-th data line is disposed between the first voltageline and the second voltage line adjacent to the first voltage line inthe second direction.

In an exemplary embodiment, the first display substrate may furtherinclude a second transistor including a second control electrodeconnected to the scan line, a first electrode connected to the firstcontrol electrode and a second electrode connected to the overlapelectrode, a third voltage line which is parallel with the scan line andtransfers a second driving signal and a third transistor including athird control electrode connected to the third voltage line, a firstelectrode connected to the first voltage line and a second electrodeconnected to the overlap electrode.

In an exemplary embodiment, the first display substrate may furtherinclude a first insulating interlayer disposed between the first controlelectrode and the extension electrode, where the first insulatinginterlayer includes a high dielectric constant material.

In an exemplary embodiment, the first display substrate may furtherinclude a second insulating interlayer disposed between the extensionelectrode and the m-th data line and a third insulating interlayerdisposed between the m-th data line and the overlap electrode.

In an exemplary embodiment, during a first period of a frame period, thefirst voltage line may receive a low voltage of the first drivingsignal, the second voltage line may receive a high voltage of the firstpower source signal, the third voltage line may receive a high voltageof the second driving signal, and the n-th scan line may receive a highvoltage of the scan signal.

In an exemplary embodiment, during a second period of the frame period,the first voltage line may receive the low voltage of the first drivingsignal, the second voltage line may receive a low voltage of the firstpower source signal lower than the low voltage of the first drivingsignal, the third voltage line may receive a low voltage of the seconddriving signal, and the n-th scan line may receive the high voltage ofthe scan signal.

In an exemplary embodiment, during a third period of the frame period,the first voltage line may receive the low voltage of the first drivingsignal, the second voltage line may receive the high voltage of thefirst power source signal, the third voltage line may receive the lowvoltage of the second driving signal, the n-th scan line may receive thehigh voltage of the scan signal during an n-th horizontal period of thethird period, and the m-th data line may receive a data voltagecorresponding to an n-th horizontal line.

In an exemplary embodiment, during the n-th horizontal period, the firstand second capacitors may be connected to each other in series, wherethe data voltage corresponding to the n-th horizontal line may bedivided by a voltage division ratio of the first and second capacitorsand the divided data voltage may be applied to the first controlelectrode.

In an exemplary embodiment, the m-th data line may receive a referencevoltage before a data voltage corresponding to a first horizontal lineof a plurality of horizontal lines is applied to the m-th data line, andafter a data voltage corresponding to a last horizontal line of theplurality of horizontal lines is applied to the m-th data line.

In an exemplary embodiment, the m-th data line may receive the referencevoltage before the first voltage line receives the high voltage of thefirst driving signal, where the reference voltage may be equal to orlower than a lowest voltage of a data voltage range.

In an exemplary embodiment, during a fourth period of the frame period,the first voltage line may receive a high voltage of the first drivingsignal, the second voltage line may receive the high voltage of thefirst power source signal, the third voltage line may receive the lowvoltage of the second driving signal, and the n-th scan line may receivea low voltage of the scan signal.

In an exemplary embodiment, a difference voltage between the highvoltage and the low voltage of the first driving signal may be appliedto the first control electrode, and a driving current corresponding tothe data voltage which is applied to the first control electrode may beapplied to the organic light emitting diode when the first transistor isturned on.

In an exemplary embodiment, the first transistor in the first displaysubstrate may be an N-type transistor.

According to the invention, in the pixel structure of the highresolution including the data line overlapping a control electrode ofthe first transistor, the control electrode has a substantially sameshape as that of the channel area of the first transistor overlappingthe control electrode so that an overlap area of the data line and thechannel area may decrease. Therefore, the parasitic capacitanceoccurring by the control electrode and the data line may decrease andthus, the display quality may be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the invention will becomemore apparent by describing in detailed exemplary embodiments thereofwith reference to the accompanying drawings, in which:

FIG. 1 is a circuit diagram illustrating an exemplary embodiment of apixel circuit;

FIG. 2 is a plan view illustrating an exemplary embodiment of a pixelcircuit;

FIG. 3 is a cross-sectional view taken along line I-I′ of the exemplaryembodiment of the pixel circuit of FIG. 2;

FIGS. 4 to 8 are cross-sectional views illustrating an exemplaryembodiment of a method of manufacturing a display apparatus;

FIG. 9 is a diagram illustrating an exemplary embodiment of a method ofdriving a pixel circuit; and

FIG. 10 is a waveform diagram illustrating an exemplary embodiment of amethod of driving a pixel circuit.

DETAILED DESCRIPTION

Hereinafter, the invention will be explained in detail with reference tothe accompanying drawings. This invention may, however, be embodied inmany different forms, and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this invention will be thorough and complete, and will fully conveythe scope of the invention to those skilled in the art. Like referencenumerals refer to like elements throughout.

It will be understood that when an element is referred to as being “on”another element, it can be directly on the other element or interveningelements may be therebetween. In contrast, when an element is referredto as being “directly on” another element, there are no interveningelements present.

It will be understood that, although the terms “first,” “second,”“third” etc. may be used herein to describe various elements,components, regions, layers and/or sections, these elements, components,regions, layers and/or sections should not be limited by these terms.These terms are only used to distinguish one element, component, region,layer or section from another element, component, region, layer orsection. Thus, “a first element,” “component,” “region,” “layer” or“section” discussed below could be termed a second element, component,region, layer or section without departing from the teachings herein

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” and “the” are intended to include the plural forms,including “at least one,” unless the content clearly indicatesotherwise. “Or” means “and/or.” As used herein, the term “and/or”includes any and all combinations of one or more of the associatedlisted items. It will be further understood that the terms “comprises”and/or “comprising,” or “includes” and/or “including” when used in thisspecification, specify the presence of stated features, regions,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

Furthermore, relative terms, such as “lower” or “bottom” and “upper” or“top,” may be used herein to describe one element's relationship toanother element as illustrated in the Figures. It will be understoodthat relative terms are intended to encompass different orientations ofthe device in addition to the orientation depicted in the Figures. In anexemplary embodiment, when the device in one of the figures is turnedover, elements described as being on the “lower” side of other elementswould then be oriented on “upper” sides of the other elements. Theexemplary term “lower,” can therefore, encompasses both an orientationof “lower” and “upper,” depending on the particular orientation of thefigure. Similarly, when the device in one of the figures is turned over,elements described as “below” or “beneath” other elements would then beoriented “above” the other elements. The exemplary terms “below” or“beneath” can, therefore, encompass both an orientation of above andbelow.

“About” or “approximately” as used herein is inclusive of the statedvalue and means within an acceptable range of deviation for theparticular value as determined by one of ordinary skill in the art,considering the measurement in question and the error associated withmeasurement of the particular quantity (i.e., the limitations of themeasurement system). For example, “about” can mean within one or morestandard deviations, or within ±30%, 20%, 10%, 5% of the stated value.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and theinvention, and will not be interpreted in an idealized or overly formalsense unless expressly so defined herein

Exemplary embodiments are described herein with reference to crosssection illustrations that are schematic illustrations of idealizedembodiments. As such, variations from the shapes of the illustrations asa result, for example, of manufacturing techniques and/or tolerances,are to be expected. Thus, embodiments described herein should not beconstrued as limited to the particular shapes of regions as illustratedherein but are to include deviations in shapes that result, for example,from manufacturing. In an exemplary embodiment, a region illustrated ordescribed as flat may, typically, have rough and/or nonlinear features.Moreover, sharp angles that are illustrated may be rounded. Thus, theregions illustrated in the figures are schematic in nature and theirshapes are not intended to illustrate the precise shape of a region andare not intended to limit the scope of the claims.

FIG. 1 is a circuit diagram illustrating a pixel circuit according to anexemplary embodiment.

Referring to FIG. 1, the pixel circuit PC of a high resolution mayinclude a first transistor T1, a second transistor T2, a thirdtransistor T3, a first capacitor Cst, a second capacitor Cpr and anorganic light emitting diode OLED.

According to the exemplary embodiment, the first, second and thirdtransistors T1, T2 and T3 may be an N-type transistor, for example. Eachof the first, second and third transistors T1, T2 and T3, which are theN-type transistors, is turned on when a high voltage is applied to acontrol electrode and is turned off when a low voltage is applied to thecontrol electrode. In the exemplary embodiment, the high voltage may bean ON voltage for turning on the transistor, and the low voltage may bean OFF voltage for turning off the transistor, for example.

The first transistor T1 may include a first control electrode CE1connected to a first node N1, a first electrode E11 connected to asecond voltage line VL2 and a second electrode E12 connected to a secondnode N2. The second voltage line VL2 receives a first power sourcesignal ELVDD.

The first power source signal ELVDD may have a high voltagecorresponding to a normal power source voltage and a low voltage whichis predetermined for driving the pixel circuit PC. The first powersource signal ELVDD may have the low voltage during a compensationperiod during which a threshold voltage of the first transistor T1 iscompensated and have the high voltage during a remaining period of theframe period except for the compensation period.

The second transistor T2 may include a second control electrode CE2connected to an n-th scan line SLn, a first electrode E21 connected tothe first node N1 and a second electrode E22 connected to the secondnode N2. The n-th scan line SLn receives an n-th scan signal S(n). Then-th scan signal S(n) has a high voltage for turning on the secondtransistor T2 and a low voltage for turning off the second transistorT2. The second transistor T2 may diode-couple the first transistor T1during the compensating period.

The third transistor T3 may include a third control electrode CE3connected to a third voltage line VL3, a first electrode E31 connectedto a first voltage line VL1 and a second electrode E32 connected to thesecond node N2. The first voltage line VL1 receives a first drivingsignal Vinit.

The first driving signal Vinit may have a high voltage and a low voltagewhich are predetermined for driving the pixel circuit PC. The firstdriving signal Vinit may have the high voltage during an emission periodduring which the organic light emitting diode OLED emits a light andhave a low voltage during a remaining period of the frame period exceptfor the emission period.

The third voltage line VL3 receives a second driving signal Vcomp. Thesecond driving signal Vcomp may have a high voltage for turning on thethird transistor T3 and a low voltage for turning off the thirdtransistor T3.

The first capacitor Cst is connected to the first voltage line VL1 andthe first node N1. The first capacitor Cst may store a voltage appliedto the first node N1.

The second capacitor Cpr is connected to the second node N2 and an m-thdata line DLm. The second capacitor Cpr may store a data voltage DATAapplied to the m-th data line DLm.

The first and second capacitors Cst and Cpr may be connected to thefirst node N1 in series when the second transistor T2 is turned on, andthe data voltage DATA is divided by a resistance ratio of the first andsecond capacitors Cst and Cpr. Then, divided data voltage DATA may beapplied to the first node N1.

The organic light emitting diode OLED may include an anode electrodeconnected to the second node N2 and a cathode electrode which receivesthe second power voltage ELVSS.

When the first transistor T1 is turned on, a driving currentcorresponding to the data voltage DATA applied to the first node N1 isapplied to the organic light emitting diode OLED. Then, the organiclight emitting diode OLED may emit the light.

Although not shown in drawings, at least one of the second and thirdtransistors T2 and T3 may have a dual gate structure to avoid a leakagecurrent.

FIG. 2 is a plan view illustrating a pixel circuit according to anexemplary embodiment.

Referring to FIGS. 1 and 2, the pixel circuit of the high resolution isdisposed in a pixel circuit area PA. The pixel circuit may include afirst voltage line VL1, a second voltage line VL2, a third voltage lineVL3, an n-th scan line SLn, an m-th data line DLm, a first transistorT1, a second transistor T2, a third transistor T3, a first capacitor Cstand a second capacitor Cpr.

The first voltage line VL1 transfers a first driving signal Vinit andextends in the first direction D1.

The second voltage line VL2 transfers a first power source signal ELVDDand extends in the first direction D1.

The third voltage line VL3 transfers a second driving signal Vcomp andextends in the second direction D2.

The n-th scan line SLn transfers an n-th scan signal S(n) and extends inthe second direction D2.

The m-th data line DLm transfers a data voltage DATA and extends in thefirst direction D1. The m-th data line DLm is disposed substantially ina central area of the pixel circuit area PA. As shown in FIG. 2, them-th data line DLm may be disposed between the first and second voltagelines VL1 and VL2.

The first transistor T1 may include a first control electrode CE1, afirst electrode E11 and a second electrode E12. The first controlelectrode CE1 may be disposed as an island shape in the central area ofthe pixel circuit area PA. The first electrode E11 may be defined in aportion area of the second voltage line VL2 which is connected to anactive pattern ACT through a first contact part CH1. The secondelectrode E12 may be defined in a portion area of the second capacitorCpr which is connected to an active pattern ACT through a second contactpart CH2. The first control electrode CE1 may overlap a first channelarea ca1 of the active pattern ACT and have a substantially same shapeas that of the first channel area ca1.

The second transistor T2 may include a second control electrode CE2, afirst electrode E21 and a second electrode E22. The second controlelectrode CE2 may be defined in a portion area of the n-th scan lineSLn. The first electrode E21 may be defined as an electrode which isconnected to an active pattern ACT through a third contact part CH3. Thesecond electrode E22 may be defined in a portion area of the secondcapacitor Cpr which is connected to an active pattern ACT through thesecond contact part CH2. The first electrode E21 may be connected to thefirst control electrode CE1 of the first transistor T1 through a fourthcontact part CH4. The second control electrode CE2 may overlap a secondchannel area ca2 of the active pattern ACT. As shown in FIG. 2, thesecond transistor T2 may have a dual gate structure which includes thesecond control electrode CE2 overlapping two second channel areas ca2.

The third transistor T3 may include a third control electrode CE3, afirst electrode E31, and a second electrode E32. The third controlelectrode CE3 may be defined in a portion area of the third voltage lineVL3. The first electrode E31 may be defined in a portion area of thethird voltage line VL3 which is connected to the active pattern ACTthrough a fifth contact part CH5. The second electrode E32 may bedefined in a portion area of the second capacitor Cpr which is connectedto the active pattern ACT through the second contact part CH2. The thirdcontrol electrode CE3 may overlap a third channel area ca3 of the activepattern ACT.

The third voltage line VL3 may be connected to a third voltage line VL3which is disposed in an adjacent pixel circuit area through a sixthcontact part CH6 and a connection electrode EE.

The first capacitor Cst may include an extension electrode which isconnected to the first voltage line VL1 and extends in the seconddirection D2 from the first voltage line VL1. The first capacitor Cstmay be defined by the extension electrode and the first controlelectrode CE1 of the first transistor T1 overlapping the extensionelectrode. The first capacitor Cst may include a first capacitorelectrode CSE1 and a second capacitor electrode CSE2 which overlap eachother. According to the exemplary embodiment, the first capacitorelectrode CSE1 may be the first control electrode CE1 and the secondcapacitor electrode CSE2 may be the extension electrode extending fromthe first voltage line VL1.

The second capacitor Cpr may include an overlap electrode which overlapsthe m-th data line DLm, and may be defined by the overlap electrode andthe m-th data line DLm which overlap the overlap electrode. The secondcapacitor Cpr may include a third capacitor electrode CPE1 and a fourthcapacitor electrode CPE2 which overlap each other. According to theexemplary embodiment, the third capacitor electrode CPE1 may be the m-thdata line DLm and the fourth capacitor electrode CPE2 may be the overlapelectrode.

According to the exemplary embodiment, the first control electrode CE1of the first transistor T1 has a substantially same shape as that of thefirst channel area ca1 which overlaps the first control electrode CE1 sothat an overlap area of the first control electrode CE1 and the m-thdata line DLm may decrease and a parasitic capacitance of the firstcontrol electrode CE1 and the m-th data line DLm may decrease. Thus,luminance defects between pixels connected to the m-th data line DLm maybe decreased and eliminated.

FIG. 3 is a cross-sectional view taken along line I-I′ of FIG. 2according to an exemplary embodiment. FIGS. 4 to 8 are cross-sectionalviews illustrating a method of manufacturing a display apparatusaccording to an exemplary embodiment.

Referring to FIGS. 2, 3 and 4, the display apparatus may include a firstdisplay substrate 100, a second display substrate 200 opposing the firstdisplay substrate 100 and a spacer coating layer 300 disposed betweenthe first and second display substrates 100 and 200.

The first display substrate 100 may include a first base substrate 111.

The base substrate 111 may include an insulation material. In anexemplary embodiment, the base substrate 111 may include a glass, atransparent plastic, a transparent metal oxide, etc., for example.

The active pattern ACT may be disposed on the base substrate 111. Theactive pattern ACT may include silicon. In an alternative exemplaryembodiment, the active pattern ACT may include a semiconductor oxideincluding a binary compound (ABx), a ternary compound (ABxCy), aquaternary compound (ABxCyDz), etc., which include indium, zinc,gallium, tin, titanium, aluminum, hafnium (Hf), zirconium (Zr),magnesium (Mg), etc., for example. These compounds may be used alone orin combination thereof.

The active pattern ACT may include first to sixth areas a1, a2, a3, a4,a5 and a6 and first to third channel areas ca1, ca2 and ca3.

The first to sixth areas a1, a2, a3, a4, a5 and a6 may be doped with animpurity. The first to sixth areas a1, a2, a3, a4, a5 and a6 may befirst and second electrodes of first, second and third transistors T1,T2 and T3.

The first channel area ca1 may be disposed between the first and secondareas a1 and a2, and correspond to a first channel area of the firsttransistor T1. The second channel area ca2 may be disposed between thethird and fourth areas a3 and a4 and correspond to a second channel areaof the second transistor T2. The third channel area ca3 may be disposedbetween the fifth and sixth areas a5 and a6 and correspond to a thirdchannel area of the third transistor T3.

A gate insulating layer 112 may be disposed on the active pattern ACT.The gate insulating layer 112 may include a silicon compound, metaloxide, etc. In an exemplary embodiment, the gate insulation layer mayinclude silicon oxide, silicon nitride, silicon oxynitride, aluminumoxide, tantalum oxide, hafnium oxide, zirconium oxide, titanium oxide,etc., for example, which may be used alone or in combination thereof. Inan exemplary embodiment, the gate insulation layer 112 may have amultilayer structure including a silicon oxide layer and silicon nitridelayer, for example.

A first conductive pattern which is patterned from a first conductivelayer may be disposed on the gate insulating layer 112. The firstconductive layer may include metal, alloy, metal nitride, conductivemetal oxide, transparent conductive material, etc., which may be usedalone or in combination thereof.

The first conductive pattern may include the n-th scan line SLn, thecontrol electrode CE2 of the second transistor T2, the third voltageline VL3, the control electrode CE3 of the third transistor T3, thecontrol electrode CE1 of the first transistor T1, and the firstcapacitor electrode CSE1 of the first capacitor Cst.

The n-th scan line SLn may extend in the second direction D2.

The first control electrode CE1 of the first transistor T1 is disposedas an island shape in a central area of the pixel circuit area PA, andhas a substantially same shape as that of the first channel area ca1which overlaps the first control electrode CE1. The first controlelectrode CE1 may fully cover the first channel area ca1. A distance dtof an edge portion of the first channel area ca1 and an edge portion ofthe first control electrode CE1 may be less than about 0.5 micrometers(μm), for example.

The second control electrode CE2 of the second transistor T2 may bedefined in a portion area of the n-th scan line SLn.

The control electrode CE3 of the third transistor T3 may be defined in aportion area of the third voltage line VL3.

The third voltage line VL3 may be disposed in parallel with the n-thscan line SLn.

The first capacitor electrode CSE1 of the first capacitor Cst may bedefined in a portion area of the control electrode CE1.

Referring to FIGS. 2, 3 and 5, a first insulating interlayer 113 may bedisposed on the first conductive pattern. In an exemplary embodiment,the first insulating interlayer 113 may include a silicon oxide, asilicon nitride, a silicon oxynitride, and etc, for example. These maybe used alone or in combination with each other.

According to the exemplary embodiment, the first insulating interlayer113 may include a high dielectric constant material (high-k) so thatcapacitance-reduction according to area-reduction of the first controlelectrode CE1 of the first transistor T1 may be compensated.

In an exemplary embodiment, the high dielectric constant material mayinclude ZrOx, AlOx, etc., for example.

A third contact part CH3, a fourth contact part CH4 and a fifth contactpart CH5 may be defined in the pixel circuit area PA. The gateinsulating layer 112 and the first insulating interlayer 113 are etchedto define the third and fifth contact parts CH3 and CH5. The insulatinginterlayer 113 are etched to define the fourth contact part CH4.

A second conductive pattern which is patterned from a second conductivelayer, may be disposed on the first insulating interlayer 113. Thesecond conductive layer metal, alloy, metal nitride, conductive metaloxide, transparent conductive material, etc., which may be used alone orin combination thereof.

The second conductive pattern may include the first voltage line VL1, asecond capacitor electrode CSE2 of the first capacitor Cst, a firstelectrode E21 of the second transistor T2 and the first electrode E31 ofthe third transistor T3.

The first voltage line VL1 may extend in the first direction D1.

The second capacitor electrode CSE2 of the first capacitor Cst may beconnected to the first voltage line VL1 and extend in the seconddirection D2 from the first voltage line VL1. The first capacitor Cstmay be defined by the first electrode CSE1 of the first conductivepattern and the second capacitor electrode CSE2 of the second conductivepattern overlapping the first electrode CSE1.

A first end portion of the first electrode E21 may be connected to theactive pattern ACT through the third contact part CH3 and a second endportion of the first electrode E21 may be connected to the controlelectrode CE1 of the first transistor T1 through the fourth contact partCH4.

The first electrode E31 of the third transistor T3 may be defined in aportion area of the first voltage line VL1 and be connected to theactive pattern ACT through the fifth contact part CH5.

Referring to FIGS. 2, 3 and 6, a second insulating interlayer 114 may bedisposed on the second conductive pattern. The pixel circuit area PA mayinclude a sixth contact part CH6 in which the first and secondinsulating interlayers 113 and 114 are etched.

A third conductive pattern which is patterned from a third conductivelayer, may be disposed on the second insulating interlayer 114. Thethird conductive pattern may include the m-th data line DLm, a thirdcapacitor electrode CPE1 of the second capacitor Cpr and a connectionelectrode EE.

The m-th data line DLm may extend in the first direction D1 and bedisposed in the central area of the pixel circuit area PA.

The third capacitor electrode CPE1 of the second capacitor Cpr mayextend from the m-th data line DLm.

The connection electrode EE may be connected to the third voltage lineVL3 and a third voltage line VL3 which is disposed in an adjacent pixelcircuit area, through the sixth contact part CH6.

Referring to FIGS. 2, 3 and 7, a third insulating interlayer 115 may bedisposed on the third conductive pattern. A first contact part CH1 and asecond contact part CH2 in which the gate insulating layer 112, thefirst insulating interlayer 113, the second insulating interlayer 114and the third insulating interlayer 115 are etched may be defined in thepixel circuit area PA.

A fourth conductive pattern which is patterned from a fourth conductivelayer may be disposed on the third insulating interlayer 115.

The fourth conductive pattern may include the second voltage line VL2,the first electrode E11 of the first transistor T1, a fourth capacitorelectrode CPE2 of the second capacitor Cpr, the second electrode E12 ofthe first transistor T1, the second electrode E22 of the secondtransistor T2 and the second electrode E32 of the third transistor T3.As shown in FIG. 7, the fourth conductive pattern may further include afirst voltage line VL1_U overlapping the first voltage line VL1. Thefirst voltage line VL1_U may be connected to the first voltage line VL1of the second conductive pattern through a contact part CH8 and have adouble-line structure.

The second voltage line VL2 may extend in the first direction D1 and maydefine a width of the pixel circuit area along the first direction D1together with the first voltage line VL1 in the adjacent pixel circuitarea PA.

The first electrode E11 of the first transistor T1 may be defined in aportion area of the second voltage line VL2 connected to the activepattern ACT through the first contact part CH1.

The fourth capacitor electrode CPE2 of the second capacitor Cpr may havean island shape and be disposed in the central area of the pixel circuitarea PA. The second capacitor Cpr may be defined by the third capacitorelectrode CPE1 of the third conductive pattern and the fourth capacitorelectrode CPE2 of the fourth conductive pattern overlapping the thirdcapacitor electrode CPE1.

The second electrode E12 of the first transistor T1, the secondelectrode E22 of the second transistor T2 and the second electrode E32of the third transistor T3 may defined in a portion area of the fourthcapacitor electrode CPE2 connected to the active pattern ACT through thesecond contact part CH2.

Referring to FIGS. 2, 3 and 8, a fourth insulating interlayer 116 may bedisposed on the fourth conductive pattern. The fourth insulatinginterlayer 116 may be provided with a high thickness to sufficientlycover the fourth conductive pattern.

A seventh contact part CH7 in which the fourth insulating interlayer 116is etched may be defined in the pixel circuit area PA.

A first pixel electrode PE1 may be disposed on the fourth insulatinginterlayer 116. The first pixel electrode PE1 may correspond to theanode electrode of the organic light emitting diode OLED.

A pixel defining layer 117 may be disposed on the fourth insulatinginterlayer 116 on which the first pixel electrode PE1 is disposed.

The pixel defining layer 117 may be etched to define an opening whichexposes a portion area of the first pixel electrode PE1 and then, theorganic light emitting layer EL may be disposed in the opening. Thus,the organic light emitting layer EL may be disposed on the first pixelelectrode PE1 exposed through the opening of the pixel defined layer117.

A second pixel electrode PE2 may be disposed on the organic lightemitting layer EL. The second pixel electrode PE2 may correspond to thecathode electrode of the organic light emitting diode OLED (refer toFIG. 1). The second pixel electrode PE2 may be commonly disposed in theplurality of pixel circuit areas.

The spacer coating layer 300 may be disposed on the first displaysubstrate 100.

Then, the first display substrate 100 on which the spacer coating layer300 is formed, may be combined with the second display substrate 200.The second display substrate 200 may include a second base substrate 211and a color filter layer CF.

FIG. 9 is a diagram illustrating a method of driving a pixel circuitaccording to an exemplary embodiment. FIG. 10 is a waveform diagramillustrating a method of driving a pixel circuit according to anexemplary embodiment.

Referring to FIGS. 9 and 10, the pixel circuit PC may receive aplurality of input signals. The plurality of input signals may includethe first power source signal ELVDD applied to the second voltage lineVL2, the first driving signal Vinit applied to the first voltage lineVL1, the second driving signal Vcomp applied to the third voltage lineVL3, an n-th scan signal S(n) applied to an n-th scan line SLn, a datavoltage DATA applied to an m-th data line DLm and the second powersource signal ELVSS applied to the cathode electrode of the organiclight emitting diode OLED.

The frame period may include a first period ‘a’ during which the anodeelectrode of the organic light emitting diode OLED is initialized, asecond period ‘b’ during which the threshold voltage of the firsttransistor T1 is compensated, a third period ‘c’ during which the datavoltage DATA is applied to the pixel and a fourth period ‘d’ duringwhich the organic light emitting diode OLED emit the light.

Referring to the first period ‘a’, the first voltage line VL1 receives alow voltage initL of the first driving signal Vinit.

The second voltage line VL2 receives a high voltage ELVDDH of the firstpower source signal ELVDD. The high voltage ELVDDH of the first powersource signal ELVDD may have a voltage of a normal positive power sourcesignal.

In an exemplary embodiment, the low voltage initL of the first drivingsignal Vinit may be about −2.2 volts (V), the high voltage ELVDDH of thefirst power source signal ELVDD may be about 7 V, the low voltage ELVDDLof the first power source signal ELVDD may be about −7 V, and the secondpower source signal ELVSS may be about 0 V, for example.

The third voltage line VL3 receives a high voltage VGH of the seconddriving signal Vcomp. The high voltage VGH of the second driving signalVcomp may have a turn-on voltage for turning on the third transistor T3.

The n-th scan line SLn receives a high voltage VGH of the n-th scansignal S(n). The high voltage VGH of the n-th scan signal S(n) may havea turn-on voltage for turning on the second transistor T2. In anexemplary embodiment, the high voltage VGH of the scan signal may beabout 10 V, for example.

The m-th data line DLm receives the reference voltage Vref. Thereference voltage Vref may be equal to or lower than a lowest voltage ina voltage range of the data voltage DATA. In an exemplary embodiment,when the voltage range of the data voltage DATA is about 0.5 V to about7.5 V, the reference voltage Vref may be equal to or lower than about0.5 V, for example.

During the first period ‘a’, the anode electrodes of the organic lightemitting diodes OLED in all pixels may be initialized by the low voltageinitL of the first driving signal Vinit, simultaneously.

Referring to the second period ‘b’, the first voltage line VL1 receivesthe low voltage initL of the first driving signal Vinit.

The second voltage line VL2 receives a low voltage ELVDDL of the firstpower source signal ELVDD. In an exemplary embodiment, the low voltageELVDDL of the first power source signal ELVDD may be about −7 V, forexample.

The third voltage line VL3 receives a low voltage VGL of second drivingsignal Vcomp. The low voltage VGL of the second driving signal Vcomp mayhave a turn-off voltage for turning off the third transistor T3. In anexemplary embodiment, the low voltage VGL of the second driving signalVcomp may be about −10 V, for example.

The n-th scan line SLn successively receives the high voltage VGH of then-th scan signal S(n).

The m-th data line DLm successively receives the reference voltage Vref.

During the second period ‘b’, the threshold voltages of the firsttransistors T1 in all pixels may be simultaneously compensated using thesum voltage of the low voltage ELVDDL of the first power source signalELVDD and the threshold voltage of corresponding first transistor T1.

Referring to the third period ‘c’, the first voltage line VL1 receivesthe low voltage initL of the first driving signal Vinit.

The second voltage line VL2 receives a high voltage ELVDDH of the firstpower source signal ELVDD.

The third voltage line VL3 receives the low voltage VGL of the seconddriving signal Vcomp.

The n-th scan line SLn receives the high voltage VGH of the n-th scansignal S(n) during an n-th horizontal period nH of the third period ‘c’.

The m-th data line DLm receives a data voltage Vdata(n) insynchronization with the high voltage VGH of the n-th scan signal S(n).

During the n-th horizontal period nH, the first and second capacitorsCst and Cpr are connected to each other in series, the data voltageVdata(n) corresponding to the n-th horizontal line is divided by avoltage division ratio of the first and second capacitors Cst and Cpr,and then the divided data voltage Vdata(n) is applied to the first nodeN1.

Referring to the plan view of the pixel circuit shown in FIG. 2, them-th data line DLm overlaps the first control electrode CE1 and thefirst control electrode CE1 overlaps the fourth capacitor electrode CPE2of the second capacitor Cpr that is the second node N2.

As described above, when the first control electrode CE1 that is thefirst node N1 overlaps the m-th data line DLm and the fourth capacitorelectrode CPE2 of the second capacitor Cpr, a first parasiticcapacitance Cp1 occurs between the m-th data line DLm and the firstcontrol electrode E11 and a second parasitic capacitance Cp2 occursbetween the first control electrode E11 and the fourth capacitorelectrode CPE2.

A voltage applied to the first node N1 may be increased by the firstparasitic capacitance Cp1. Thus, a leakage current occurs by the firsttransistor T1. An anode voltage of the organic light emitting diode OLEDmay be increased by the leakage current. When the anode voltage of theorganic light emitting diode OLED increase, a voltage applied to thefirst node N1 may be increased by the second parasitic capacitance Cp2.

Therefore, data coupling occurs by the first and second parasiticcapacitances Cp1 and Cp2 and the organic light emitting diode OLED doesnot limit the light of a target luminance. Thus, a display quality maybe decreased.

In contrast, according to the exemplary embodiment, a size of the firstcontrol electrode CE1 of the first transistor T1, that is the firstnode, may decrease so that the first and second parasitic capacitancesCp1 and Cp2 may decrease. Thus, the display quality may be improved.

In addition, the m-th data line DLm may receive the reference voltageVref before a first horizontal period 1H in which a data voltageVdata(1) corresponding to a first horizontal line (e.g., first scanline) among a plurality of horizontal lines (e.g., scan lines) isapplied to the m-th data line DLm and after a last horizontal period,i.e., Nth horizontal period NH, in which a data voltage Vdata(N)corresponding to a last horizontal line (e.g., last scan line) among theplurality of horizontal lines is applied to the m-th data line DLm.Therefore, the plurality of data lines may be maintained into thereference voltage Vref during an early period and a latter period of thethird period ‘c’.

Referring to the fourth period ‘d’, the first voltage line VL1 receivesa high voltage initH of the first driving signal Vinit.

A difference voltage between the high voltage initH and the low voltageinitL of the first driving signal Vinit is applied to the first node N1,and then the first transistor T1 is turned on. The high voltage initH ofthe first driving signal Vinit may be determined based on a turn-onvoltage of the first transistor T1.

In an exemplary embodiment, the high voltage initH of the first drivingsignal Vinit may be about 6.5 V, for example.

The second voltage line VL2 receives the high voltage ELVDDH of thefirst power source signal ELVDD.

The third voltage line VL3 receives the low voltage VGL of the seconddriving signal Vcomp. The n-th scan line SLn receives the low voltageVGL of the n-th scan signal S(n). The m-th data line DLm receives thereference voltage Vref

During the fourth period ‘d’, driving current corresponding to the datavoltage applied to the first node N1 may be provided to the organiclight emitting diode OLED and the organic light emitting diode OLED mayemit the light.

According to the exemplary embodiments, in the pixel structure of thehigh resolution including the data line overlapping a control electrodeof the first transistor, the control electrode has a substantially sameshape as that of the channel area of the first transistor overlappingthe control electrode so that an overlap area of the data line and thechannel area may decrease. Thus, the parasitic capacitance occurring bythe control electrode and the data line may decrease and the displayquality may be improved.

The invention may be applied to a display device and an electronicdevice including the display device. In an exemplary embodiment, theinvention may be applied to various electronic devices such as acomputer monitor, a laptop, a digital camera, a cellular phone, a smartphone, a smart pad, a television, a personal digital assistant (“PDA”),a portable multimedia player (“PMP”), a MP3 player, a navigation system,a game console, a video phone, etc.

The foregoing is illustrative of the invention and is not to beconstrued as limiting thereof. Although a few exemplary embodiments ofthe invention have been described, those skilled in the art will readilyappreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel teachings andadvantages of the invention. Accordingly, all such modifications areintended to be included within the scope of the invention as defined inthe claims. In the claims, means-plus-function clauses are intended tocover the structures described herein as performing the recited functionand not only structural equivalents but also equivalent structures.Therefore, it is to be understood that the foregoing is illustrative ofthe invention and is not to be construed as limited to the specificexemplary embodiments disclosed, and that modifications to the disclosedexemplary embodiments, as well as other exemplary embodiments, areintended to be included within the scope of the appended claims. Theinvention is defined by the following claims, with equivalents of theclaims to be included therein.

What is claimed is:
 1. A display substrate comprising: a data lineextending in a first direction; a first transistor comprising a firstchannel area overlapping the data line and a first control electrodewhich overlaps the first channel area and has a substantially same shapeas that of the first channel area in an overlap area in which the firstcontrol electrode overlaps the first channel area; a scan line extendingin a second direction crossing the first direction; a first voltage linewhich extends in the first direction and transfers a first drivingsignal; a first capacitor comprising an extension electrode whichoverlaps the first control electrode and extends in the second directionfrom the first voltage line; and a second capacitor comprising anoverlap electrode overlapping the data line.
 2. The display substrate ofclaim 1, further comprising: a second voltage line which is connected tothe first transistor and transfers the first power source signal,wherein the data line is disposed between the first voltage line and thesecond voltage line adjacent to the first voltage line in the seconddirection.
 3. The display substrate of claim 2, further comprising: asecond transistor comprising a second control electrode connected to thescan line, a first electrode connected to the first control electrodeand a second electrode connected to the overlap electrode; a thirdvoltage line which is parallel with the scan line and transfers a seconddriving signal; and a third transistor comprising a third controlelectrode connected to the third voltage line, a first electrodeconnected to the first voltage line and a second electrode connected tothe overlap electrode.
 4. The display substrate of claim 1, furthercomprising: a first insulating interlayer disposed between the firstcontrol electrode and the extension electrode and comprising a highdielectric constant material.
 5. The display substrate of claim 4,further comprising: a second insulating interlayer disposed between theextension electrode and the data line; and a third insulating interlayerdisposed between the data line and the overlap electrode.
 6. The displaysubstrate of claim 1, further comprising: an organic light emittingdiode comprising an anode electrode connected to the overlap electrode,a cathode electrode which receives a second power source signal and anorganic light emitting layer disposed between the anode electrode andthe cathode electrode.
 7. A display apparatus comprising: a firstdisplay substrate comprising an m-th data line extending in a firstdirection, a first transistor comprising a first channel areaoverlapping the m-th data line and a first control electrode whichoverlaps the first channel area and has a substantially same shape asthat of the first channel area in an overlap area in which the firstcontrol electrode overlaps the first channel area, an n-th scan linewhich extends in a second direction crossing the first direction andreceives a scan signal, a first capacitor comprising an extensionelectrode overlapping the first control electrode, a second capacitorcomprising an overlap electrode overlapping the m-th data line, and anorganic light emitting diode comprising an anode electrode connected tothe overlap electrode and an organic light emitting layer; and a seconddisplay substrate opposing to the first display substrate.
 8. Thedisplay apparatus of claim 7, wherein the first display substratefurther comprises: a first voltage line which extends in the firstdirection and transfers a first driving signal; and a second voltageline which is connected to the first transistor and transfers a firstpower source signal, wherein the m-th data line is disposed between thefirst voltage line and the second voltage line adjacent to the firstvoltage line in the second direction.
 9. The display apparatus of claim8, wherein the first display substrate further comprises: a secondtransistor comprising a second control electrode connected to the n-thscan line, a first electrode connected to the first control electrodeand a second electrode connected to the overlap electrode; a thirdvoltage line which is parallel with the n-th scan line and transfers asecond driving signal; and a third transistor comprising a third controlelectrode connected to the third voltage line, a first electrodeconnected to the first voltage line and a second electrode connected tothe overlap electrode.
 10. The display apparatus of claim 7, wherein thefirst display substrate further comprises a first insulating interlayerdisposed between the first control electrode and the extensionelectrode, and wherein the first insulating interlayer comprises a highdielectric constant material.
 11. The display apparatus of claim 10,wherein, the first display substrate further comprises: a secondinsulating interlayer disposed between the extension electrode and them-th data line; and a third insulating interlayer disposed between them-th data line and the overlap electrode.
 12. The display apparatus ofclaim 9, wherein, during a first period of a frame period, the firstvoltage line receives a low voltage of the first driving signal, thesecond voltage line receives a high voltage of the first power sourcesignal, the third voltage line receives a high voltage of the seconddriving signal, and the n-th scan line receives a high voltage of thescan signal.
 13. The display apparatus of claim 12, wherein, during asecond period of the frame period, the first voltage line receives thelow voltage of the first driving signal, the second voltage linereceives a low voltage of the first power source signal lower than thelow voltage of the first driving signal, the third voltage line receivesa low voltage of the second driving signal, and the n-th scan linereceives the high voltage of the scan signal.
 14. The display apparatusof claim 13, wherein, during a third period of the frame period, thefirst voltage line receives the low voltage of the first driving signal,the second voltage line receives the high voltage of the first powersource signal, the third voltage line receives the low voltage of thesecond driving signal, the n-th scan line receives the high voltage ofthe scan signal during an n-th horizontal period of the third period,and the m-th data line receives a data voltage corresponding to an n-thhorizontal line.
 15. The display apparatus of claim 14, wherein duringthe n-th horizontal period, the first and second capacitors areconnected to each other in series, wherein the data voltagecorresponding to the n-th horizontal line is divided by a voltagedivision ratio of the first and second capacitors and the divided datavoltage is applied to the first control electrode.
 16. The displayapparatus of claim 14, wherein the m-th data line receives a referencevoltage before a data voltage corresponding to a first horizontal lineof a plurality of horizontal lines is applied to the m-th data line, andafter a data voltage corresponding to a last horizontal line of theplurality of horizontal lines is applied to the m-th data line.
 17. Thedisplay apparatus of claim 16, wherein the m-th data line receives thereference voltage before the first voltage line receives the highvoltage of the first driving signal, wherein the reference voltage isequal to or lower than a lowest voltage of a data voltage range.
 18. Thedisplay apparatus of claim 14, wherein during a fourth period of theframe period, the first voltage line receives a high voltage of thefirst driving signal, the second voltage line receives the high voltageof the first power source signal, the third voltage line receives thelow voltage of the second driving signal, and the n-th scan linereceives a low voltage of the scan signal.
 19. The display apparatus ofclaim 18, wherein a difference voltage between the high voltage and thelow voltage of the first driving signal is applied to the first controlelectrode, and a driving current corresponding to the data voltage whichis applied to the first control electrode is applied to the organiclight emitting diode when the first transistor is turned on.
 20. Thedisplay apparatus of claim 7, wherein the first transistor in the firstdisplay substrate is an N-type transistor.